Lubricant for electrophotography, lubricant applying unit, process cartridge, and image forming apparatus

Abstract

An lubricant for electrophotography is applied to a latent image carrier that is supplied with toner having a sphericity of 0.94 or more. The lubricant for electrophotography is added with an inorganic additive having the following relationship: 2 Y /1000≦ X≦Y /10 where Y is a toner particle size (micrometer), and X is an inorganic additive particle size (micrometer).

1 . A lubricant for electrophotography applied to a latent image carrier to which toner having a sphericity of equal to or more than 0.94 is supplied, wherein 
 an inorganic additive is added to the lubricant, and    the inorganic additive satisfies     2 Y/ 1000≦ X≦Y/ 10   where Y is a particle size of the toner in micrometer, and X is a particle size of the inorganic additive in micrometer.    
     
     
         2 . The lubricant according to  claim 1 , wherein the inorganic additive is a substance containing at least one of silica, titania, alumina, magnesia, zirconia, ferrite, and magnetite.  
     
     
         3 . The lubricant according to  claim 1 , wherein a main component of the lubricant is either of fatty acid metal salt and fluorine particles.  
     
     
         4 . The lubricant according to  claim 3 , wherein an amount of addition of the inorganic additive ranges from 1 weight percent to 30 weight percent with respect to the main component.  
     
     
         5 . A lubricant applying unit that applies a lubricant for electrophotography to a latent image carrier, the lubricant applying unit comprising a brush roller that rotates around a rotational axis, and is in contact with the latent image carrier, wherein 
 toner having a sphericity of equal to or more than 0.94 is supplied to the latent image carrier,    an inorganic additive is added to the lubricant,    the inorganic additive satisfies     2 Y/ 1000≦ X≦Y/ 10   where Y is a particle size of the toner in micrometer, and X is a particle size of the inorganic additive in micrometer,    the lubricant is a molded lubricant that is molded as a solid block, and    the brush roller slides along, and scrapes off the molded lubricant so that the lubricant is applied to the latent image carrier.    
     
     
         6 . The lubricant applying unit according to  claim 5 , further comprising a new-latent-image-carrier detector that detects whether the latent image carrier is used for a first time, wherein 
 when it is detected that the latent image carrier is used for the first time, the lubricant is applied to the latent image carrier.    
     
     
         7 . The lubricant applying unit according to  claim 6 , wherein a frictional coefficient of the latent image carrier after applying the lubricant is equal to or less than 0.4.  
     
     
         8 . The lubricant applying unit according to  claim 5 , further comprising a pushing unit that pushes the molded lubricant against the brush roller by a force of equal to or more than 200 meter-Newtons.  
     
     
         9 . The lubricant applying unit according to  claim 5 , wherein 
 the brush roller rotates in a direction of rotation of the latent image carrier, and    a peripheral speed ratio of the brush roller to the latent image carrier ranges from 0.8 to 1.2.    
     
     
         10 . A process cartridge comprising: 
 a latent image carrier;    at least one of 
 a charging unit that causes a charging member to contact or to be close to the latent image carrier to charge the latent image carrier;  
 a developing unit that deposits toner on a latent image on the latent image carrier to develop the latent image with the toner; and  
 a cleaning unit that cleans the toner remaining on the latent image carrier with a cleaning blade; and  
   a lubricant applying unit that applies a lubricant for electrophotography to the latent image carrier, the lubricant applying unit including a brush roller that rotates around a rotational axis, and is in contact with the latent image carrier, wherein    toner having a sphericity of equal to or more than 0.94 is supplied to the latent image carrier,    an inorganic additive is added to the lubricant,    the inorganic additive satisfies       2   Y/   1000≦   X≦Y/ 10   where Y is a particle size of the toner in micrometer, and X is a particle size of the inorganic additive in micrometer,    the lubricant is a molded lubricant that is molded as a solid block, and    the brush roller slides along, and scrapes off the molded lubricant so that the lubricant is applied to the latent image carrier.    
     
     
         11 . An image forming apparatus comprising a process cartridge that includes 
 a latent image carrier;    at least one of 
 a charging unit that causes a charging member to contact or to be close to the latent image carrier to charge the latent image carrier;  
 a developing unit that deposits toner on a latent image on the latent image carrier to develop the latent image with the toner; and  
 a cleaning unit that cleans the toner remaining on the latent image carrier with a cleaning blade; and  
   a lubricant applying unit that applies a lubricant for electrophotography to the latent image carrier, the lubricant applying unit including a brush roller that rotates around a rotational axis, and is in contact with the latent image carrier, wherein    toner having a sphericity of equal to or more than 0.94 is supplied to the latent image carrier,    an inorganic additive is added to the lubricant,    the inorganic additive satisfies     2 Y/ 1000≦ X≦Y/ 10   where Y is a particle size of the toner in micrometer, and X is a particle size of the inorganic additive in micrometer,    the lubricant is a molded lubricant that is molded as a solid block, and    the brush roller slides along, and scrapes off the molded lubricant so that the lubricant is applied to the latent image carrier.    
     
     
         12 . The image forming apparatus according to  claim 11 , wherein the toner has 
 a volume-average particle size ranging from 3 micrometers to 8 micrometers; and    a ratio of a volume-average particle size to a number-average particle size ranging from 1.00 to 1.40.    
     
     
         13 . The image forming apparatus according to  claim 11 , wherein the toner has 
 a shape factor SF- 1  ranging from 100 to 180; and    a shape factor SF- 2  ranging from 100 to 180.    
     
     
         14 . The image forming apparatus according to  claim 11 , wherein the toner is substantially spherical.  
     
     
         15 . The image forming apparatus according to  claim 11 , wherein 
 the toner has a shape defined by a long axis r 1 , a short axis r 2 , and a thickness r 3 , where r 1 ≧r 2 ≧r 3 ,    a ratio r 2 /r 1  ranges from 0.5 to 1.0, and    a ratio r 3 /r 2  ranges from 0.7 to 1.0.    
     
     
         16 . The image forming apparatus according to  claim 11 , wherein the toner is obtained by subjecting a toner material solution to either one or both of crosslinking reaction and extension reaction in an aqueous medium, the toner material solution being obtained by dispersing at least polyester prepolymer having a functional group containing a nitrogen atom, polyester, a colorant, and a mold release agent into an organic solvent.  
     
     
         17 . An image forming apparatus comprising a lubricant applying unit that applies a lubricant for electrophotography to a latent image carrier, wherein 
 the lubricant applying unit includes a brush roller that rotates around a rotational axis, and is in contact with the latent image carrier,    toner having a sphericity of equal to or more than 0.94 is supplied to the latent image carrier,    an inorganic additive is added to the lubricant,    the inorganic additive satisfies     2 Y/ 1000≦ X≦Y/ 10   where Y is a particle size of the toner in micrometer, and X is a particle size of the inorganic additive in micrometer,    the lubricant is a molded lubricant that is molded as a solid block, and    the brush roller slides along, and scrapes off the molded lubricant so that the lubricant is applied to the latent image carrier.    
     
     
         18 . The image forming apparatus according to  claim 17 , wherein the toner has 
 a volume-average particle size ranging from 3 micrometers to 8 micrometers; and    a ratio of a volume-average particle size to a number-average particle size ranging from 1.00 to 1.40.    
     
     
         19 . The image forming apparatus according to  claim 17 , wherein the toner has 
 a shape factor SF- 1  ranging from 100 to 180; and    a shape factor SF- 2  ranging from 100 to 180.    
     
     
         20 . The image forming apparatus according to  claim 17 , wherein the toner is substantially spherical.  
     
     
         21 . The image forming apparatus according to  claim 17 , wherein the toner has a shape defined by a long axis r 1 , a short axis r 2 , and a thickness r 3 , where r 1 ≧r 2 ≧r 3 , 
 a ratio r 2 /r 1  ranges from 0.5 to 1.0, and    a ratio r 3 /r 2  ranges from 0.7 to 1.0.    
     
     
         22 . The image forming apparatus according to  claim 17 , wherein the toner is obtained by subjecting a toner material solution to either one or both of crosslinking reaction and extension reaction in an aqueous medium, the toner material solution being obtained by dispersing at least polyester prepolymer having a functional group containing a nitrogen atom, polyester, a colorant, and a mold release agent into an organic solvent.